Hey there Christos.  You may already have noticed this,
but your change in sys/sys/cdefs.h broke building libc
in the current tree, at least for i386 (but I think it's
mi).  __UNCONST is defined by libc/stdio/vfprintf.c, as
well.  Perhaps it should just be removed there, but I
don't know that it's not also elsewhere in the whole
of NetBSD.

   Thanks...

                         - Chris